<section class="section">
  <h2>Containers</h2>
  <article>
    <h3>This is an article</h3>
    <p>This is the content of the first article</p>
    <section>
      <h4>First section</h4>
      <p>Content of the first section</p>
    </section>
    <aside>
      <h4>Aside</h4>
      <p>Content of the aside</p>
    </aside>
    <section>
      <h4>Second section</h4>
      <p>Content of the second section</p>
    </section>
  </article>
  <article>
    <h3>This is another article</h3>
    <p>This is the content of the second article</p>
  </article>
  <section class="section">
    <details class="demo">
      <summary>View code</summary>
      <pre><code>&lt;article&gt;
  &lt;h3&gt;This is an article&lt;/h3&gt;
  &lt;p&gt;This is the content of the first article&lt;/p&gt;
  &lt;section&gt;
    &lt;h4&gt;First section&lt;/h4&gt;
    &lt;p&gt;Content of the first section&lt;/p&gt;
  &lt;/section&gt;
  &lt;aside&gt;
    &lt;h4&gt;Aside&lt;/h4&gt;
    &lt;p&gt;Content of the aside&lt;/p&gt;
  &lt;/aside&gt;
  &lt;section&gt;
    &lt;h4&gt;Second section&lt;/h4&gt;
    &lt;p&gt;Content of the second section&lt;/p&gt;
  &lt;/section&gt;
&lt;/article&gt;
&lt;article&gt;
  &lt;h3&gt;This is another article&lt;/h3&gt;
  &lt;p&gt;This is the content of the second article&lt;/p&gt;
&lt;/article&gt;</code></pre>
    </details>
  </section>
</section>